Field of the Disclosure
Embodiments of the present disclosure generally relate to a nonvolatile memory device, specifically a resistive random-access memory (ReRAM) device and select transistor.
Description of the Related Art
Nonvolatile memory is memory capable of retaining stored information even after having been power cycled. Nonvolatile memory is becoming more popular because of the small size/high density, low power consumption, fast read and write rates, and retention. Flash memory is a common type of nonvolatile memory due to high density and low fabrication costs. Flash memory is a transistor-based memory device that uses multiple gates per transistor and quantum tunneling for storing the information on its memory device. However, flash memory uses a block-access architecture that can result in long access, erase, and write times. Flash memory also suffers from low endurance, high power consumption, and scaling limitations.
The constantly increasing speed of electronic devices and storage demand drive new requirements for nonvolatile memory. New types of memory, such as resistive random access memory (ReRAM), are being developed as flash memory replacements to meet these demands. Resistive memories refer to technology that uses varying cell resistance to store information. ReRAM refers to the subset that uses metal oxides as the storage medium. In order to switch a ReRAM cell, an external voltage with specific polarity, magnitude, and duration is applied. However, ReRAM typically operates at a significantly high current. As such, ReRAM necessitates a large sized access transistor for each cell which ultimately increases the area and hence the cost.
Thus, there is a need in the art for an improved ReRAM memory device.